Demonstrates scientific concepts by means of experiments, including step-by-step instructions, lists of materials, troubleshooter's guide, and interpretation and explanation of the results.

Vols. 5-6 by M. Rae Nelson; Allison McNeill, project editor.

v. 1. A-Ec -- v. 2. El-L -- v. 3. M-Sc -- v. 4. So-Z -- v. 5. A-O -- v. 6. P-Z.